refactor: use build-time version injection instead of runtime package.json read

- Add scripts/generate-version.js to generate src/generated/version.ts at build time
- Update utils.ts to import VERSION from generated file instead of reading package.json
- Add prebuild script to package.json to run version generation before build
- Add src/generated/ to .gitignore (auto-generated files)

This makes version lookup resilient in bundled/serverless environments where
package.json may not be available at runtime.

Agent-Id: agent-0d00d75b-1ac5-4e85-a310-90e1af295ee3

Author: richhankins

.gitignore

@@ -1,2 +1,3 @@
 node_modules
 dist
+src/generated/